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To determine possible human and environmental health risks, organochlorine pesticide residues were determined in vegetables grown in floodplains along the Ouémé River near Lowé in Bénin. Testing of vegetables found 13 pesticides with ΣDDT, α-endosulfan, Σdrin, and lindane being most important. The same pesticides were also detected in plants eaten by bovine cattle, sheep, and herbivorous fish. Human pesticide intake by vegetable consumption was compared with tolerable daily intake (TDI) values reported by the World Health Organization. Pesticide intake by fish consumption was estimated from residue levels in whole fish collected from the Ouémé River in 2004 and reported earlier. Fish consumption does not pose a risk for human health, but consuming vegetables that contain pesticide residues may lead to exceedance of TDI values. Based on these findings, concerns are warranted, and more work is needed to understand the full exposure profile for the local population.

Sewage sludge application to soils is regulated by its total metal content. However, the real risk of metals is determined by the fraction that is biologically available. The available fraction is highly related to the strength of metal binding by the matrix, which is a dynamic process. The evaluation of the fate of metals in time can contribute increased accuracy of ecological risk assessment. Aiming to evaluate short-term changes in metal availability when metals were applied to soil directly (metal-spiked) or by way of an organic matrix (sludge-amended), a laboratory experiment was performed using open microcosms filled with agricultural soil. A concentration gradient of industrial sludge (11, 15, 55, and 75 t/ha) that was contaminated predominantly with chromium, copper, nickel, and zinc, or soil freshly spiked with the same concentrations of these metals, were applied on top of the agricultural soil. After 0, 3, 6, and 12 weeks, total (HNO(3) 69 %) and 0.01 M CaCl(2)-extractable metal concentrations in soil and metal content in the percolates were measured. Results demonstrated that comparison between sludge-amended and metal-spiked soils may give important information about the role of sludge matrix on metal mobility and availability in soil. In sludge-amended soils, extractable-metal concentrations were independent of the sludge concentration and did not change over time. In metal-spiked soils, metal extractability decreased with time due to ageing and transport of metals to deeper layers. In general, the sludge matrix increased the adsorption of metals, thus decreasing their mobility in soils.

Studies of the effects of endocrine-disrupting compounds (EDCs) on invertebrates are still largely underrepresented. This work aims to fill this gap by assessing the effects of bisphenol A (BPA) and vinclozolin (Vz) on the terrestrial isopod Porcellio scaber (common rough woodlouse). Male adult and sexually undifferentiated juvenile woodlice were exposed to the toxicants. Effects on molting regime and growth were investigated independently for males and female woodlice after sexual differentiation. Both chemicals elicited developmental toxicity to P. scaber by causing overall decreased growth. Nevertheless, BPA induced molting, whereas Vz delayed it. Although the LC50 values for juvenile and adult survival were fairly similar, juvenile woodlice showed an increased chronic sensitivity to both chemicals, and female woodlice were most the sensitive to BPA. We recommend the use of adults, juveniles, female, and male woodlice, as well as a large range of toxicant concentrations, to provide valuable information regarding differential dose responses, effects, and threshold values for EDCs.

The variation of acute toxicity data among nematode species belonging to different taxonomic and ecological groups was investigated. Twelve different nematode species were extracted from the soil and directly exposed to cadmium and pentachlorophenol. LC50-values were estimated after 24, 48, 72, and 96 h of exposure in aqueous solutions. The species exhibited large differences in sensitivity. LC50-values (72 h) for pentachlorophenol ranged from 0.5 to more than 34.5 mumol/L and for cadmium from 29 to more than 800 mumol/L. These toxicity data could be described by a log-logistic distribution function. LC50-values for cadmium were not correlated with those for pentachlorophenol. Species of the subphylum Secernentia were less sensitive to pentachlorophenol than species of the subphylum Penetrantia, while no differences were observed for cadmium. In addition, no relationship was found between toxicity data and life-history strategies. Slow colonizers (K-strategists, sensu lato) were not more sensitive to cadmium and pentachlorophenol than opportunistic species (r-strategists, sensu lato). Nematodes appeared to be as sensitive to pentachlorophenol as other soil invertebrates. Nematodes were generally tolerant to cadmium.